1 #coding=utf-8 2 from sympy import * 3 import numpy as np 4 from sympy import * 5 import math 6 import matplotlib.pyplot as plt 7  8 plt.close() 9 fig = plt.figure()10 #网格可见11 plt.grid(True)12 plt.axis([0, 5, -2, 25])13 #开启交互14 plt.ion()15 #plt.title("牛顿法")16 #设置xy轴的名称17 plt.xlabel("X")18 plt.ylabel("Y")19 x = np.linspace(0, 10, 100)20 y = x**2-221 plt.plot(x, y, label="$y$", color="red", linewidth=1)22 plt.show()23 24 25 #定义变量x26 x = Symbol('x')27 #定义函数f28 f = x**2-229 x0=5.030 while(1):31     y0=x0**2-232     g = diff(f,x,1)33     k = g.subs(x,x0)34     # y1 = f.sub(x,x0)35     b = y0-k*x036     x1=-b/k37     plt.plot([x0,x0],[0,y0])38     plt.plot([x1,x0],[0,y0])39     print(x1)40     if (abs(x1 - x0) < 0.00001):41         x0=x142         break43     x0=x144     plt.pause(0.5)45 show_res = '[x=' + str(x0) +  ']'46 plt.text(1,1, show_res)47 while True:48     plt.pause(0.05)